1. Field of the Invention
The present invention relates to a bearing having needle rollers which is applied to business machines or the like.
2. Description of the Prior Art
As shown in FIG. 4, needle rollers b are rotatably held within a generally annular retainer a having a side wall a1, the rollers b being disposed circumferentially with proper distances therebetween and protruding in radial direction outwardly from the outer circumferential surface and inwardly from the inner circumferential surface of the retainer a. The assembly of the rollers b and the retainer a is combined with an outer race c and an inner race d so that the surfaces of the rollers are rotatably in contact with the inner circumferential surface of the outer race c and the outer circumferential surface of the inner race d.
With the prior art bearing above-mentioned, since the retainer is provided with the side wall a1, the outer race c which supports the retainer a therein tends to be large in size. Also, the side wall a1 tends to impose frictional drag on the inner surface of the outer race. Further, even if the inner race d is eliminated, the needle rollers b cannot directly contact a shaft.